Felmenia Stingray was a genius magician. She quickly became the most distinguished magician of the Astel Kingdom after her discovery of white fire magic, which had the power to burn anything.

However, the world is in peril due to the Demon King. The kingdom's court magicians perform a summoning ritual for heroes and bring forth a hero and two youths, a boy and a girl. Unlike the girl, the young man refused to fight the Demon King alongside the Hero and demanded to be sent back to his world. The kingdom, angry with his behavior, locked him away.

Now Felmenia stands before the same young man with her strongest magic, the white flame, being completely useless and asks who he is. It was already obvious to her that this man was far stronger than she was. To this he simply responds.

"Yakagi Suimei, a magician."

From AOC Translations:
Tsukishiro Nina moves to Ruberia, a small country surrounded by the ocean and roses. But suddenly, she was bitten by a young Loup-Garou, a beast that is said to only exist in legends. Once bitten, Nina herself turned into one of them and was forced into "Abigaile" an academy prison on an island where all the beasts are exiled to. What cruel fate awaits the pitiful Nina...!?

Alexandra is the duchess of the Kingdom of Tarraconensis. It was only the day before the absolution event that she realized that she was the villainous daughter of an otome game! It's clear that she'll be denounced and her engagement will be broken tomorrow.
But I don't want to be condemned honestly! I'd rather show my eyes to the people who despised me! With only 24 hours left, Alexandra begins to make a breakthrough in her desperate situation.

From ShoujoMagic:
On Kabuchi-jima, an island ruled by Princess Kaguya, ten children were raised as sacrificial victims. Several of the children thought they had escaped their fate when they escaped the island. But nearly a decade later, the kids are still dying in the order and at the time they would have as sacrifices... Their only hope now is to reunite and return to the island to seek out and destroy the source--the legend, the blood-lusting Moon Princess--before time runs out.

In 2002 Kaguya Hime received the 47th annual Shogakukan Manga Award for shoujo.

College student Otonari Otoya is a boy who lacks self-esteem and dreams of being reborn into a different dimension. One day while playing a [video] game, he accidentally clicks on an ad, and trips into another world?!?!
He's surprised but delighted, until he realizes that something's strange. A whole group of guys are treating him too kindly, almost like he's a girl! Could it be that the world Otonari was transported into... is an otome game?!?!

A veteran adventurer was preparing for his retirement when his former disciple returned to the village, intending to recruit the old man to his party. Filled with regret due to an incident that happened in his first party, the old man rejected his offer. Being affected by his disciple’s adventurous spirit, the old man leaves in hopes of reigniting his long-lost dream, to become the strongest adventurer that ever lived.

The protagonist of the series is the lecherous Satonaka Ikkou, who transforms into a super-monk (being able to perform mass exorcisms) by his lust for the girls he lives with. He lives in the Saienji Buddhist Temple as a Buddhist priest-in-training together with six other nuns: Amanogawa Haruka, Ikuina Sumi, sisters Sugai Sakura & Hinata, Nambu Chitose and Atouda Yuuko, each of whom represent one of the bosatsu of the six lower realms of the traditional Buddhist cosmology. Chitose is the other main character and has a strange relationship with Ikkou; he seems to be in all the wrong places at all the wrong times, but they really care for each other in all actuality. A side effect of Ikkou using his ultimate power is that immediately afterwards, he turns into an even bigger pervert than he normally is. The series is about Ikkou's self-destructive power and his attempts to control it.

Ruu Brandel, a genius wizard with a talent for thousands of years. One day helped a beautiful aristocratic daughter, Franc and was to be assigned to “Magic Girls' Gakuen” where he acts as a teacher! Now, the “non-standard” teacher life by the strongest wizard opens!

(Source: MangaUpdates)

"Ecchi stuff that also may have a story...."

Used to be a Hero, and before that a Sage, Lex has reincarnated. Again. This time he just wants to be a NORMAL adventurer…

The Demon King led his army of demons to wipe out the human race. The Hero, Kail, and his allies attacked the Demon King's castle to defeat the Demon King. The Demon King is slain, but at what cost? Kail lost all of his allies throughout the war. Friends, family, lovers, comrades. All dead, and he is dying.
As Kail's life ebbs away in the Demon King's chamber, he notices a strange gem that the Demon King had coveted and approaches this relic to grab it; after an intense light glows, he is sent years into the past. After recovering from the initial shock, now in his younger body, he decides to avoid making the same mistakes of his first time through these years and to become stronger.

The manga focuses on a hero who is married, but monster girls seeking children of heroic lineage keep coming after him to steal him away. The hero's wife chooses to deal with the monster girls herself.

Ryotaro is a boy who loves robots and lives out in the country with his three sisters, but he's headed to Tokyo for high school. Before leaving, he runs across a humanoid military robot and has a fateful encounter with its pilot, a cute teenage girl who calls herself La Vie en Rose. Ryotaro will almost certainly meet her again in Tokyo, considering his family connection to the production of these humanoid robots--his father worked with them.

Manaka Makoto, a 24-year-old salaryman without a girlfriend, wakes up one morning suddenly changed into a female, and a knockout at that who attracts just about everyone of the opposite sex. And when he learns through a magical being that the only way he’s going to become male again is by getting aroused (as a woman) he tries to find a way back without any success. But when success finally comes and he switches back, he discovers that he will switch back and forth ANY time he gets close to someone sexually, and there are exceptions…

A world where wars are fought with spies. With a mission success rate of 100%, the remarkable, yet rather difficult to deal with, spy Klaus is being tasked with an almost impossible mission by the agency, harboring an insane 90% chance of failure and death…which for some reason involves eight inexperienced girls?!

The story begins with Yggdrasil, a popular online game which is quietly shut down on its last day. Our protagonist Momonga decided to stay until the last moment in his beloved game and wait for the force logout. Unexpectedly, the server did not shut down and Momonga is stuck in his skeleton body and got transferred to another world. "The powerful Overlord" needs now to discover a new world and face the continuous challenges.

Having no parents, friends, or place in society, this ordinary man strives to take over the new world the game has become.

“If my true heart leaks, I wonder what feelings I will convey...” In this world, if your dissatisfaction rate reaches a certain level, your "Split" will satisfy your desire for you; Fission Syndrome.

Makoto, a first-year high school student who fears Splitting and confessing to his crush, was accustomed to keeping his feelings hidden… Until, one day, in front of Makoto's eyes, his crush develops Fission Syndrome?! Moreover, it was a terrible Split that appeared...

Received a grand prize at the 3rd Manga Box Editorial Club. "I can't hide my thoughts in this world," the Split Love manga is finally published!

The one who defeated various ranked dangerous monsters, the one who sealed 6 demon lords, the one who is onlooked by God. Elm, the dragon knight who wields several legendary equipment, humanity's strongest man, has continued to work for the Bangs kingdom. He accepts SSS rank requests, but he is mocked with the name "Subcontractor Knight". He continues this harsh labor, until his dragon partner, Baha, suggests for him to retire. So Elm and Baha depart for an unknown location to start their slow lives…

Having become overwhelming strong, a mage was bored with his life and decided to reincarnate in another era about 1000 years later.

But after reincarnation, the mage now known as Kurt saw a world where magic had declined, and the mages of the era are overall much weaker than those of 1000 years ago.

It also seems that Kurt is being looked down upon for his "Gold Magic" as it is called "Defective Magic Power" in this era.

In order to investigate the mysterious decline of magic in this era, Kurt enrolled in the Magic Academy at the Royal Capital and showed his extraordinary talent where he would become unparalleled in this second life of his too!?

Inspite of defeating the demon lord, the hero Noel Viga was betrayed by his friends and his kingdom. “I don’t care about anything anymore! I’m going to live my life the way I want to!”. The second life of the former hero begins.